Image sensor and electronic apparatus including the image sensor

ABSTRACT

An image sensor may include a pixel array including a plurality of two-dimensionally arranged pixels. Each pixel may include a first meta-photodiode absorbing light of a first wavelength band; a second meta-photodiode absorbing light in a second wavelength band; and a third meta-photodiode absorbing light of a third wavelength band, wherein the first meta-photodiode, the second meta-photodiode, and the third meta-photodiode may be arranged in an area having a size less than a diffraction limit. The arrangement form of the first meta-photodiode, the second meta-photodiode, and the third meta-photodiode arranged in the plurality of pixels in a central portion of the pixel array may be the same as the arrangement form of the first meta-photodiode, the second meta-photodiode, and the third meta-photodiode arranged in the plurality of pixels in a periphery of the pixel array.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims priority under 35 U.S.C. § 119to Korean Patent Application No. 10-2022-0079277, filed on Jun. 28,2022, in the Korean Intellectual Property Office, the disclosure ofwhich is incorporated by reference herein in its entirety.

BACKGROUND 1. Field

The disclosure relates to image sensors and electronic apparatusesincluding the image sensors.

2. Description of the Related Art

An image sensor generally senses a color of incident light using a colorfilter. However, because the color filter absorbs light of a color otherthan light of a corresponding color, the efficiency of light utilizationmay be reduced. For example, when an RGB color filter is used, becausethe RGB color filter transmits only ⅓ of incident light and absorbs theremaining ⅔ of the incident light, the light utilization efficiency isonly about 33%. As such, most of the light loss of an image sensor maybe caused by the color filter. Accordingly, a method of separating acolor into each pixel of an image sensor without using a color filterhas been attempted.

On the other hand, as the demand for higher resolutions increases, pixelsizes are gradually getting smaller, which may limit a color separationfunction. In addition, in a color separation method, energy entering aunit pixel is divided and absorbed by R, G, and B effective areas, thus,each sub-pixel is in charge of one color, and due to under-sampling thatis basically present in a signal processing process, resolutiondegradation may occur. Accordingly, a method of implementing a fullcolor pixel suitable for realizing a high resolution is being sought.

SUMMARY

Provided are image sensors having full color pixels and an electronicapparatuses including the image sensors.

Also, provided are image sensors having substantially uniform absorptionspectra at a central portion and a periphery having different chief rayangles of incident light, and electronic apparatuses including the imagesensors.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments of the disclosure.

According to an aspect of the disclosure, there is provided an imagesensor including: a pixel array including a plurality oftwo-dimensionally arranged pixels, wherein each of the plurality ofpixels comprises: a first meta-photodiode configured to selectivelyabsorb light of a first wavelength band; a second meta-photodiodeconfigured to selectively absorb light of a second wavelength banddifferent from the first wavelength band; and a third meta-photodiodeconfigured to selectively absorb light of a third wavelength banddifferent from the first wavelength band and second wavelength band,wherein, the first meta-photodiode, the second meta-photodiode, and thethird meta-photodiode are arranged in an area having a size equal to orless than a diffraction limit, wherein the first meta-photodiode, thesecond meta-photodiode, and the third meta-photodiode of one or morefirst pixels in a central portion of the pixel array, among theplurality of pixels, are arranged in a same form as the firstmeta-photodiode, the second meta-photodiode, and the thirdmeta-photodiode of one or more second pixels in a periphery of the pixelarray, among the plurality of pixels.

In the central portion and the periphery of the pixel array, the firstmeta-photodiodes arranged in the plurality of pixels may have a samefirst structure, the second meta-photodiodes may have a same secondstructure, and the third meta-photodiodes may have a same thirdstructure.

In each of the plurality of pixels, the following condition may besatisfied: W/2+40 nm>S, where S is a spacing between twometa-photodiodes adjacent in a first direction among the firstmeta-photodiode, the second meta-photodiode, and the thirdmeta-photodiode and W is a sum of widths of the two adjacentmeta-photodiodes.

In each of the plurality of pixels, a spacing between twometa-photodiodes adjacent in the first direction among the firstmeta-photodiode, the second meta-photodiode, and the thirdmeta-photodiode may be about 150 nm or less, and is at least ½ of a sumof widths of the two adjacent meta-photodiodes.

In each of the plurality of pixels, a spacing between twometa-photodiodes adjacent in the first direction among the firstmeta-photodiode, the second meta-photodiode, and the thirdmeta-photodiode may be ⅓ or less of the diffraction limit.

The central portion of the pixel array is a first area in which incidentlight may be vertically incident, and the periphery of the pixel arraysurrounds the central portion and is a second area in which incidentlight may be obliquely incident.

The pixel array may further include: an optical plate arranged to facelight incident surfaces of the plurality of pixels and configured tochange a traveling direction of incident light to be perpendicular tothe light incident surfaces of the plurality of pixels.

The optical plate may include a digital micro-lens array or a digitaldeflector.

Each of the first meta-photodiode, the second meta-photodiode, and thethird meta-photodiode may have a rod-shape may include: a firstconductivity-type semiconductor layer, an intrinsic semiconductor layerstacked on the first conductivity-type semiconductor layer, and a secondconductivity-type semiconductor layer stacked on the intrinsicsemiconductor layer, and wherein the first meta-photodiode, the secondmeta-photodiode, and the third meta-photodiode respectively may have afirst width, a second width, and a third width different from each otherin a direction perpendicular to a stacking direction.

The first width, the second width, and the third width may be about 50nm to about 200 nm.

The first wavelength band may be greater than the second wavelengthband, and the second wavelength band may be greater than the thirdwavelength band, and wherein the first width may be greater than thesecond width, and the second width is greater than the third width.

Heights of the first meta-photodiode, the second meta-photodiode, andthe third meta-photodiode in the stacking direction may be about 500 nmor more

The heights of the first meta-photodiode, the second meta-photodiode,and the third meta-photodiode in the stacking direction are same as eachother.

Each of the plurality of pixels may have a width of about 250 nm toabout 450 nm.

Each of the plurality of pixels may include one of the firstmeta-photodiode, one of the second meta-photodiode, and two of the thirdmeta-photodiode, and wherein the first meta-photodiode and the secondmeta-photodiode are provided in a first diagonal direction, and the twothird meta-photodiodes are provided in a second diagonal directioncrossing the first diagonal direction.

A sum of the number of the first meta-photodiodes, the secondmeta-photodiodes, and the third meta-photodiodes arranged in each of theplurality of pixels is nine, and the nine meta-photodiodes are arrangedin the form of a 3×3 array.

Each of the plurality of pixels may include one of the firstmeta-photodiodes, a plurality of the second meta-photodiodes, and aplurality of the third meta-photodiodes, and wherein the firstmeta-photodiode is located at the center of each of the plurality ofpixels.

According to another aspect of the disclosure, there is provided animage sensor including: a pixel array including a plurality oftwo-dimensionally arranged pixels, wherein each of the plurality ofpixels includes: a first meta-photodiode configured to selectivelyabsorb light of a first wavelength band; a second meta-photodiodeconfigured to selectively absorb light in a second wavelength banddifferent from the first wavelength band; and a third meta-photodiodeconfigured to selectively absorb light of a third wavelength banddifferent from the first wavelength band and second wavelength band,wherein the first meta-photodiode, the second meta-photodiode, and thethird meta-photodiode are arranged in an area having a size less than adiffraction limit, and wherein a spacing between two meta-photodiodesadjacent in a first direction among the first meta-photodiode, thesecond meta-photodiode, and the third meta-photodiode is about 150 nm orless, and the spacing is at least ½ of a sum of widths of the twoadjacent meta-photodiodes.

In an entire area of the pixel array, the first meta-photodiode, thesecond meta-photodiode, and the third meta-photodiode arranged in eachof the plurality of pixels have a same arrangement form.

According to another aspect of the disclosure, there is provided anelectronic apparatus including: a lens assembly configured to form anoptical image of an object; an image sensor configured to convert theoptical image formed by the lens assembly into an electrical signal; anda processor configured to process a signal generated by the imagesensor, wherein the image sensor includes a pixel array including aplurality of two-dimensionally arranged pixels, and each of theplurality of pixels includes: a first meta-photodiode configured toselectively absorb light of a first wavelength band; a secondmeta-photodiode configured to selectively absorb light of a secondwavelength band different from the first wavelength band; and a thirdmeta-photodiode configured to selectively absorb light of a thirdwavelength band different from the first wavelength band and secondwavelength band, wherein, the first meta-photodiode, the secondmeta-photodiode, and the third meta-photodiode are arranged in an areahaving a size less than a diffraction limit, and wherein the firstmeta-photodiode, the second meta-photodiode, and the thirdmeta-photodiode of one or more first pixels in a central portion of thepixel array, among the plurality of pixels, are arranged in a same formas the first meta-photodiode, the second meta-photodiode, and the thirdmeta-photodiode of one or more of second pixels in a periphery of thepixel array, among the plurality of pixels.

According to another aspect of the disclosure, there is provided a pixelarray including: one or more first pixels provided in a center region ofthe pixel array; and one or more second pixels provided in a peripheralregion of the pixel array, wherein each of the one or more first pixelsand the one or more second pixels including: a first meta-photodiodeconfigured to selectively absorb light of a first wavelength band; asecond meta-photodiode configured to selectively absorb light of asecond wavelength band different from the first wavelength band; and athird meta-photodiode configured to selectively absorb light of a thirdwavelength band different from the first wavelength band and secondwavelength band, wherein, the one or more first pixels and the one ormore second pixels have a width equal to or less than a diffractionlimit, and wherein the first meta-photodiode, the secondmeta-photodiode, and the third meta-photodiode of the one or more firstpixels are arranged in a same form as the first meta-photodiode, thesecond meta-photodiode, and the third meta-photodiode of the one or moreof second pixels.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the disclosure will be more apparent from the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a block diagram of an image sensor according to an exampleembodiment;

FIG. 2 is a plan view showing a pixel arrangement of a pixel array ofthe image sensor of FIG. 1 ;

FIG. 3 is a conceptual diagram schematically illustrating a cameramodule including the image sensor of FIG. 1 ;

FIG. 4 is a perspective view illustrating a structure of a pixel arrayof the image sensor of FIG. 1 ;

FIG. 5 is a plan view of the structure of the pixel array of FIG. 4 ;

FIGS. 6A and 6B are cross-sectional views taken along lines A-A and B-Bof FIG. 5 , respectively;

FIG. 7 is a table showing a comparison of color separation resultsaccording to a size of meta-photodiodes and a spacing between themeta-photodiodes with respect to different chief ray angles;

FIGS. 8A to 8C, 9A to 9C, 10A to 100, 11A to 110 and 12A to 12C aregraphs showing changes in absorption spectra of blue light, green light,and red light according to a size of meta-photodiodes and a spacingbetween meta-photodiodes compared at different chief ray angles;

FIG. 13 is a plan view illustrating a structure of a pixel array of animage sensor according to another example embodiment;

FIGS. 14A to 14C, 15A to 15C and 16A to 16C are graphs showingcomparisons of changes in absorption spectra of blue light, green light,and red light according to a width of an isolation film between pixelswith respect to different chief ray angles;

FIG. 17 shows a pixel arrangement of an image sensor according to acomparative example;

FIG. 18 is a graph showing efficiencies for each color of an imagesensor according to a comparative example;

FIG. 19 is a perspective view illustrating a schematic structure of animage sensor according to another example embodiment;

FIGS. 20 to 23 are plan views illustrating an arrangement of varioustypes of meta-photodiodes provided in one pixel in each of image sensorsaccording to other example embodiments;

FIG. 24 is a cross-sectional view illustrating a structure of a pixelarray of an image sensor according to another example embodiment;

FIG. 25 is a plan view illustrating an example nano-pattern structure ofan optical plate located at a central portion of a pixel array;

FIG. 26 shows an example phase profile of light after immediatelypassing through one digital micro-lens of an optical plate at a centralportion of a pixel array;

FIG. 27 is a plan view illustrating an example nano-pattern structure ofan optical plate located at a periphery of a pixel array;

FIG. 28 is a graph showing an example phase profile of light immediatelyafter passing through one digital micro-lens of an optical plate at aperiphery of a pixel array;

FIG. 29 is a cross-sectional view illustrating a structure of a pixelarray of an image sensor according to another example embodiment;

FIG. 30 is a schematic block diagram illustrating an electronicapparatus including an image sensor according to embodiments;

FIG. 31 is a schematic block diagram illustrating a camera module ofFIG. 30 ; and

FIGS. 32 to 41 are views illustrating various examples of electronicapparatuses to which image sensors according to embodiments are applied.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings, wherein like referencenumerals refer to like elements throughout. In this regard, the exampleembodiments may have different forms and should not be construed asbeing limited to the descriptions set forth herein. Accordingly, theexample embodiments are merely described below, by referring to thefigures, to explain aspects. As used herein, the term “and/or” includesany and all combinations of one or more of the associated listed items.Expressions such as “at least one of,” when preceding a list ofelements, modify the entire list of elements and do not modify theindividual elements of the list.

Hereinafter, image sensors and electronic apparatuses including theimage sensors will described in detail with reference to theaccompanying drawings. The example embodiments of the disclosure arecapable of various modifications and may be embodied in many differentforms. In the following drawings, like reference numerals refer to likeelements, and the size of each component in the drawings may beexaggerated for clarity and convenience of description.

Hereinafter, when a position of an element is described using anexpression “above” or “on”, the position of the element may include notonly the element being “immediately on/under/left/right in a contactmanner” but also being “on/under/left/right in a non-contact manner”.

Although the terms “first”, “second”, “third”, etc., may be used hereinto describe various elements, these terms are only used to distinguishone element from another. These terms do not limit the difference in thematerial or structure of the components.

The singular forms include the plural forms unless the context clearlyindicates otherwise. When a part “comprises” or “includes” an element inthe specification, unless otherwise defined, it is not excluding otherelements but may further include other elements.

Also, in the specification, the term “units” or “ . . . modules” denoteunits or modules that process at least one function or operation, andmay be realized by hardware, software, or a combination of hardware andsoftware. For example, according to an example, “units” or “ . . .modules” may be implemented by a processor, one or more electroniccomponents and/or circuits.

The term “above” and similar directional terms may be applied to bothsingular and plural.

With respect to operations that constitute a method, the operations maybe performed in any appropriate sequence unless the sequence ofoperations is clearly described or unless the context clearly indicatesotherwise. Also, all example terms (for example, etc.) are simply usedto explain in detail the technical scope of the disclosure, and thus,the scope of the disclosure is not limited by the examples or theexample terms as long as it is not defined by the claims.

FIG. 1 is a block diagram of an image sensor 1000 according to anexample embodiment, and FIG. 2 is a plan view showing a pixelarrangement of a pixel array 1100 of the image sensor 1000 of FIG. 1 .

Referring to FIGS. 1 and 2 , the image sensor 1000 may include the pixelarray 1100, a timing controller (T/C) 1010, a row decoder 1020, and anoutput circuit 1030. The pixel array 1100 includes two-dimensionallyarranged pixels PXs along a plurality of rows and columns. Each of thepixels PX may include a plurality of p-i-n meta-photodiodes. Theplurality of p-i-n meta-photodiodes will be described in detail belowwith reference to FIG. 4 .

The row decoder 1020 selects one row of the pixel array 1100 in responseto a row address signal output from the timing controller 1010. Theoutput circuit 1030 outputs a photo-sensing signal in column units froma plurality of pixels arranged along the selected row. To this end, theoutput circuit 1030 may include a column decoder and ananalog-to-digital converter (ADC). For example, the output circuit 1030may include a plurality of ADCs respectively provided for columnsbetween the column decoder and the pixel array 1100, or one ADC providedat an output terminal of the column decoder. The timing controller 1010,the row decoder 1020, and the output circuit 1030 may be implemented asa single chip or as separate chips. A processor for processing an imagesignal output through the output circuit 1030 may be implemented as asingle chip together with the timing controller 1010, the row decoder1020, and the output circuit 1030.′

The plurality of pixels PX constituting the pixel array 1100 may befull-color pixels, each of which may sense an arbitrary color. That is,light incident on the pixel PX may be divided for each wavelength band,for example, amounts of a red light component, a green light component,and a blue light component may be differentiated and sensed.Accordingly, the loss of light of a specific color according to a colorof a sub-pixel, which occurs in an image sensor having a color filter ofthe related art, does not occur in the image sensor 1000 according tothe example embodiment. In other words, each color component of lightincident on the pixel PX may be detected almost regardless of a positionof a region within the pixel PX. In this regard, the pixel PX of theimage sensor 1000 according to an example embodiment may be referred toas a full-color pixel or an RGB pixel in a sense of distinguishing froma red pixel, a green pixel, a blue pixel, etc., which recognize onlyspecific colors.

As illustrated in FIG. 2 , the pixels PX may be two-dimensionallyarranged, and a width p of the pixel PX may have a size equal to or lessthan a diffraction limit D. Here, the width may denote a width in onedirection defining a two-dimensional array, and the widths in bothdirections may be equal to or less than the diffraction limit D.

The diffraction limit D may denote a minimum size to which an object maybe separated and imaged, and is expressed by the following equation:

D=λ/(2NA)=λ*F.

Here, λ is a wavelength of incident light, and NA and F are numericalaperture and F-number of an imaging optical system (or lens assembly),respectively.

NA is defined as a sine value of a marginal ray angle in an imagingspace, which may denote that the larger the NA, the larger the angulardistribution of focused light. F-number is defined by a relation of1/(2NA). According to a trend towards high resolution andminiaturization of imaging systems, the marginal ray angle tends toincrease, and accordingly, modular lenses with a small F-number arebeing developed. When an ideal F-number that may be reduced is about1.0, the diffraction limit D becomes λ.

Under this condition, based on the central wavelength of blue light, thediffraction limit D may be expressed as, for example, about 450 nm. Thatis, each pixel PX constituting the pixel array 1100 may have a size ofabout 450 nm×450 nm or less. However, this dimension is an example, anda specific size may vary according to the imaging optical systemprovided together. As such, according to another example embodiment, thediffraction limit D may be different from 450 nm.

A minimum width of the pixel PX may be set according to the size andnumber of meta-photodiodes provided in the pixel PX, which are describedlater. The width of the pixel PX may be, for example, about 250 nm ormore, or about 300 nm or more, but is not limited thereto.

The image sensor 1000 described above may be applied to various opticalapparatuses such as a camera module. For example, FIG. 3 is a conceptualdiagram schematically illustrating a camera module 1880 including theimage sensor 1000 of FIG. 1 . According to an example embodiment, thecamera module may include one or more hardware components assembled tocapture an image.

Referring to FIG. 3 , the camera module 1880 may include a lens assembly1910 configured to form an optical image by focusing light reflectedfrom an object, and the image sensor 1000 configured to convert theoptical image formed by the lens assembly 1910 into an electrical imagesignal, and an image signal processor 1960 configured to process anelectrical signal output from the image sensor 1000 into an imagesignal. The camera module 1880 may also include an infrared blockingfilter provided between the image sensor 1000 and the lens assembly1910, a display panel for displaying an image formed by the image signalprocessor 1960, and a memory for storing image data formed by the imagesignal processor 1960. The camera module 1880 may be mounted in, forexample, a mobile electronic device such as a mobile phone, a notebookcomputer, a tablet PC, etc.

The lens assembly 1910 serves to focus an image of an object outside thecamera module 1880 on the image sensor 1000, more precisely, on thepixel array 1100 of the image sensor 1000. In FIG. 3 , a single lens isshown for convenience, but an actual lens assembly 1910 may include aplurality of lenses. When the pixel array 1100 is accurately positionedon a focal plane of the lens assembly 1910, light starting from a pointon an object is re-converged to a point on the pixel array 1100 throughthe lens assembly 1910. For example, light starting from any one point Aon an optical axis OX passes through the lens assembly 1910, and then,converges to the center of the pixel array 1100 on the optical axis OX.Light starting from any one point B, C, or D that is deviated from theoptical axis OX crosses the optical axis OX by the lens assembly 1910and is collected at a point in a periphery of the pixel array 1100. Forexample, in FIG. 3 , light starting from a point B above the opticalaxis OX crosses the optical axis OX and is collected at a lower edge ofthe pixel array 1100, and light starting from a point C that is lowerthan the optical axis OX crosses the optical axis OX and is collected atan upper edge of the pixel array 1100. In addition, light starting fromthe point D located between the optical axis OX and the point B iscollected at the periphery between the center and the lower edge of thepixel array 1100.

Accordingly, the light starting from the different points A, B, C, and Denters the pixel array 1100 at different angles from each otherdepending on a distance between the points A, B, C, and D and theoptical axis OX. An incident angle of light incident on the pixel array1100 is defined as a chief ray angle (CRA). A chief ray refers to a rayincident on the pixel array 1100 from a point of an object through thecenter of the lens assembly 1910, and the chief ray angle refers to anangle the chief ray makes with the optical axis OX. Light starting fromthe point A on the optical axis OX has a chief ray angle of 0 degreesand is incident perpendicularly to the central portion of the pixelarray 1100. The chief ray angle increases as the starting point movesaway from the optical axis OX.

From the viewpoint of the image sensor 1000, the chief ray angle of theincident light at the central portion of the pixel array 1100 is 0degrees, and the incident light is obliquely incident at the peripherysurrounding the central portion of the pixel array 1100. Also, the chiefray angle of the incident light increases toward the edge of the pixelarray 1100. For example, the chief ray angle of light incident on theedge of the pixel array 1100 starting from points B and C is thelargest, and the chief ray angle of light starting from point A andincident on the central portion of the pixel array 1100 is 0 degree. Inaddition, the chief ray angle of the light starting from the point D andincident on the periphery between the center and the edge of the pixelarray 1100 is less than the chief ray angle of the light starting fromthe points B and C and greater than 0 degree.

Accordingly, the chief ray angle of incident light incident on thepixels varies according to positions of the pixels in the pixel array1100. According to an example embodiment, a spacing betweenmeta-photodiodes, which will be described later, may be determined sothat absorption spectra of pixels located at the central portion of thepixel array 1100 and pixels located at the periphery of the pixel array1100 are uniform.

FIG. 4 is a detailed perspective view illustrating a structure of apixel array 1100 of the image sensor 1000 of FIG. 1 . FIG. 5 is a planview of the structure of the pixel array 1100 of FIG. 4 , and FIGS. 6Aand 6B are cross-sectional views taken along lines A-A and B-B of FIG. 5, respectively.

Referring to FIG. 4 , each of the plurality of pixels PX included in thepixel array 1100 may include a first meta-photodiode 100 configured toselectively absorb light of a first wavelength band (e.g., a redwavelength band), a second meta-photodiode 200 configured to selectivelyabsorb light of a second wavelength band (e.g., green wavelength band)different from the first wavelength band, and a third meta-photodiode300 configured to selectively absorb light of a third wavelength band(e.g., blue wavelength band) different from the first wavelength bandand the second wavelength band. According to an example embodiment, thepixel array 1100 of the image sensor 1000 may further include adielectric layer 500 filled between the first meta-photodiode 100, thesecond meta-photodiode 200, and the third meta-photodiode 300.

Also, the pixel array 1100 of the image sensor 1000 may further includea circuit board SU. The circuit board SU supports a plurality of firstmeta-photodiodes 100, a plurality of second meta-photodiodes 200, and aplurality of third meta-photodiodes 300, and may include a circuitelement for processing a signal in each pixel PX. For example, thecircuit board SU may include electrodes and wiring structures for thefirst meta-photodiode 100, the second meta-photodiode 200, and the thirdmeta-photodiode 300 provided in the pixel PX. In addition, variouscircuit elements required for the image sensor 1000 may be integratedand provided on the circuit board SU. For example, the circuit board SUmay further include a logic layer including various analog circuits anddigital circuits, and may further include a memory layer in which datais stored. The logic layer and the memory layer may be configured asdifferent layers or the same layer. Some of the circuit elementsillustrated in FIG. 1 may be provided on the circuit board SU.

The first meta-photodiode 100, the second meta-photodiode 200, and thethird meta-photodiode 300 each may be a rod-shaped vertical-typephotodiode having a dimension less than a wavelength of incident light,and may selectively absorb light of a specific wavelength band byguided-mode resonance. Absorption spectra of the first meta-photodiode100, the second meta-photodiode 200, and the third meta-photodiode 300may be determined by widths, heights, cross-sectional shapes, andarrangement forms of the first meta-photodiode 100, the secondmeta-photodiode 200, and the third meta-photodiode 300, and may bedetermined by a spacing between two adjacent meta-photodiodes among thefirst meta-photodiode 100, the second meta-photodiode 200, and the thirdmeta-photodiode 300.

Referring to FIG. 5 , each of the first meta-photodiode 100, the secondmeta-photodiode 200, and the third meta-photodiode 300 may have a firstwidth w1, a second width w2, and a third width w3 different from eachother in a direction (X direction or Y direction) perpendicular to aheight direction (Z direction) so that first meta-photodiode 100, thesecond meta-photodiode 200, and the third meta-photodiode 300selectively absorb light of different wavelength bands. That is,according to an example embodiment, the first meta-photodiode 100 mayhave the first width w1, the second meta-photodiode 200 may have thesecond width w2 and the third meta-photodiode 300 may have the thirdwidth w3, where the first width w1, the second width w2, and the thirdwidth w3 are different from each other in a direction (X direction or Ydirection) perpendicular to a height direction (Z direction). The firstwidth w1, the second width w2, and the third width w3 may have, forexample, a range of about 50 nm or more and about 200 nm or less. Thefirst width w1, the second width w2, and the third width w3 may beselected so that light of a wavelength satisfying requirements of eachguided-mode resonance among light incident on the pixel PX is guidedinside the corresponding meta-photodiode. For example, the first widthw1 may be in a range of about 100 nm to about 200 nm, the second widthw2 may be in a range of about 80 nm to about 150 nm, and the third widthw3 may be in a range of about 50 nm to about 120 nm.

The first meta-photodiode 100, the second meta-photodiode 200, and thethird meta-photodiode 300 may absorb red light, green light, and bluelight among incident light, respectively. Accordingly, a meta-photodiodehaving a greater width among the first meta-photodiode 100, the secondmeta-photodiode 200, and the third meta-photodiode 300 may absorb lightof a longer wavelength band. For example, the first width w1 may begreater than the second width w2, and the second width w2 may be greaterthan the third width w3. In FIG. 5 , circles shown around the firstmeta-photodiode 100, the second meta-photodiode 200, and the thirdmeta-photodiode 300 conceptually illustrate that red light, green light,and blue light, respectively, are guided into the first meta-photodiode100, the second meta-photodiode 200, and the third meta-photodiode 300,but are not limited thereto. Most of red light incident to an arbitraryposition in the pixel PX region may be absorbed by the firstmeta-photodiode 100, most of green light may be absorbed by the secondmeta-photodiode 200, and most of blue light may be absorbed by the thirdmeta-photodiode 300.

In addition, one pixel PX may include one first meta-photodiode 100 thatabsorbs red light, one second meta-photodiode 200 that absorbs greenlight, and two third meta-photodiodes 300 that absorbs blue light. Forexample, one first meta-photodiode 100, one second meta-photodiode 200,and two third meta-photodiodes 300 may be arranged so that a lineconnecting the centers of the four meta-photodiodes 100, 200, and 300 isa square. The first meta-photodiode 100 and the second meta-photodiode200 may be provided in a first diagonal direction of a square, and thetwo third meta-photodiodes 300 are provided in a second diagonaldirection crossing the first diagonal direction. However, thearrangement is an example. For example, meta-photodiodes may be arrangedso that a line connecting the centers of four meta-photodiodes in onepixel PX is a rectangle, or five or more meta-photodiodes may also bearranged.

In FIGS. 4 and 5 , the first meta-photodiode 100, the secondmeta-photodiode 200, and the third meta-photodiode 300 are illustratedin a cylindrical shape, but are not limited thereto. For example, thefirst meta-photodiode 100, the second meta-photodiode 200, and the thirdmeta-photodiode 300 may have an elliptical rod-shape or a polygonalrod-shape such as, a square column or a hexagonal column. In otherwords, cross-sectional shapes of the first meta-photodiode 100, thesecond meta-photodiode 200, and the third meta-photodiode 300 in adirection (X direction or Y direction) perpendicular to the heightdirection (Z direction) may have a circular, oval, or polygonal shape.When the cross-sectional shapes of the first meta-photodiode 100, thesecond meta-photodiode 200, and the third meta-photodiode 300 arecircular shape, the first width w1, the second width w2, and the thirdwidth w3 may be denoted by a first diameter, a second diameter, and athird diameter, respectively.

Referring to FIGS. 6A and 6B, a height H of the first meta-photodiode100, the second meta-photodiode 200, and the third meta-photodiode 300may be about 500 nm or more, about 1 μm or more, or about 2 μm or more.An appropriate upper limit of the height H of the first meta-photodiode100, the second meta-photodiode 200, and the third meta-photodiode 300may be set in consideration of quantum efficiency for each wavelengthand process difficulty, and may be, for example, 10 μm or less, or 5 μmor less. Light of a shorter wavelength having high energy may beabsorbed closer to an upper surface of a meta-photodiode, and light witha longer wavelength may be absorbed at a deeper position of themeta-photodiode. Accordingly, the height H of the first meta-photodiode100, the second meta-photodiode 200, and the third meta-photodiode 300may be determined in consideration of a position where light incidentinto the first meta-photodiode 100, the second meta-photodiode 200, andthe third meta-photodiode 300 is absorbed, that is, a depth positionfrom a surface thereof.

As shown in FIGS. 6A and 6B, the first meta-photodiode 100, the secondmeta-photodiode 200, and the third meta-photodiode 300 may have the sameheight. When the first meta-photodiode 100, the second meta-photodiode200, and the third meta-photodiode 300 have the same height, themanufacturing process may be easy. In this case, a height at which lightabsorption is sufficiently achieved may be selected in accordance withreference to light of a long wavelength band. However, the disclosure isnot limited thereto, and the first meta-photodiode 100, the secondmeta-photodiode 200, and the third meta-photodiode 300 may havedifferent heights from each other. For example, a meta-photodiode havinga greater height among the first meta-photodiode 100, the secondmeta-photodiode 200, and the third meta-photodiode 300 may absorb lightof a longer wavelength band. In other words, if a height of the firstmeta-photodiode 100 is h1, a height of the second meta-photodiode 200 ish2, and a height of the third meta-photodiode 300 is h3, a condition ofh1>h2>h3 may be satisfied.

Each of the first meta-photodiode 100, the second meta-photodiode 200,and the third meta-photodiode 300 is a rod-shaped p-i-n photodiode. Forexample, the first meta-photodiode 100 may include a firstconductivity-type semiconductor layer 11, an intrinsic semiconductorlayer 12 stacked on the first conductivity-type semiconductor layer 11in a third direction (Z direction), and a second conductivity-typesemiconductor layer 13 stacked on the intrinsic semiconductor layer 12in the third direction (Z direction), the second meta-photodiode 200 mayinclude a first conductivity-type semiconductor layer 21, an intrinsicsemiconductor layer 22 stacked on the first conductivity-typesemiconductor layer 21 in the third direction (Z direction), and asecond conductivity-type semiconductor layer 23 stacked on the intrinsicsemiconductor layer 22 in the third direction (Z direction), and thethird meta-photodiode 300 may include a first conductivity-typesemiconductor layer 31, an intrinsic semiconductor layer 32 stacked onthe first conductivity-type semiconductor layer 31 in the thirddirection (Z direction), and a second conductivity-type semiconductorlayer 33 stacked on the intrinsic semiconductor layer 32 in the thirddirection (Z direction). Here, a direction in which the firstconductivity-type semiconductor layers 11, 21, and 31, the intrinsicsemiconductor layers 21, 22, and 32, and the second conductivity-typesemiconductor layers 13, 23, and 33 are stacked may be the samedirection as the height direction of the first meta-photodiode 100, thesecond meta-photodiode 200, and the third meta-photodiode 300. The firstconductivity-type semiconductor layers 11, 21, and 31 may include asemiconductor material doped with a first conductivity type, the secondconductivity-type semiconductor layers 13, 23, and 33 may include asemiconductor material doped with a second conductivity-type that iselectrically opposite to the first conductivity type, and the intrinsicsemiconductor layers 12, 22, and 32 may include an undoped semiconductormaterial.

The first meta-photodiode 100, the second meta-photodiode 200, and thethird meta-photodiode 300 may be formed based on a siliconsemiconductor. For example, the first conductivity-type semiconductorlayers 11, 21, and 31 may include p-Si, the intrinsic semiconductorlayers 12, 22, and 32 may include i-Si, and the second conductivity-typesemiconductor layer 13, 23, and 33 may include n-Si. Alternatively, thefirst conductivity-type semiconductor layers 11, 21, and 31 may includen-Si, and the second conductivity-type semiconductor layers 13, 23, and33 may include p-Si. However, the semiconductor material is notnecessarily limited to silicon Si. For example, according to anotherexample embodiment, the semiconductor material of the firstmeta-photodiode 100, the second meta-photodiode 200, and the thirdmeta-photodiode 300 may include germanium Ge, a Group III-V compoundsemiconductor, or a Group II-VI compound semiconductor.

According to an example embodiment, the dielectric layer 500 filledbetween the first meta-photodiode 100, the second meta-photodiode 200,and the third meta-photodiode 300 may include a dielectric material thatis transparent to light of a wavelength band to be detected by the firstmeta-photodiode 100, the second meta-photodiode 200, and the thirdmeta-photodiode 300. In addition, the dielectric material of thedielectric layer 500 may have a refractive index less than that of thefirst meta-photodiode 100, the second meta-photodiode 200, and the thirdmeta-photodiode 300. The refractive index of the dielectric material ofthe dielectric layer 500 for light having a wavelength of about 630 nmmay be, for example, 1 or more or 2 or less. For example, the dielectriclayer 500 may include air, SiO₂, Si₃N₄, or Al₂O₃.

As described above, the first meta-photodiode 100, the secondmeta-photodiode 200, and the third meta-photodiode 300 having a width ordiameter less than a wavelength of incident light may be arranged in apixel PX having a size less than or equal to a diffraction limit of animaging optical system, for example, the lens assembly 1910. In otherwords, in one pixel PX, the first meta-photodiode 100, the secondmeta-photodiode 200, and the third meta-photodiode 300 may be arrangedin an area having a size less than or equal to a diffraction limit ofthe imaging optical system, for example, the lens assembly 1910. Then,each pixel PX may sense red light, green light, and blue light includedin incident light without using a color filter. In this regard, it maybe seen that the first meta-photodiode 100, the second meta-photodiode200, and the third meta-photodiode 300 arranged in one pixel PX allperform the role of a lens, the role of a color filter, and the role ofa photodiode by acting together.

Meanwhile, the change in absorption spectra of the first meta-photodiode100, the second meta-photodiode 200, and the third meta-photodiode 300according to a chief ray angle of incident light may be affected by aspacing between the first meta-photodiode 100, the secondmeta-photodiode 200, and the third meta-photodiode 300. Referring toFIG. 5 , the spacing between the two adjacent meta-photodiodes among thefirst meta-photodiode 100, the second meta-photodiode 200, and the thirdmeta-photodiode 300 may be defined as a distance between the centers ofthe two adjacent meta-photodiodes. For example, a first spacing Sx in afirst direction (X direction) may be defined as a distance in the firstdirection between the center of the second meta-photodiode 200 and thecenter of the third meta-photodiode 300, or may be defined as a distancein the first direction between the center of the first meta-photodiode100 and the center of the third meta-photodiode 300. In addition, asecond spacing Sy in a second direction (Y direction) is a distance inthe second direction between the center of the second meta-photodiode200 and the center of the third meta-photodiode 300, or may be definedas a distance in the second direction between the center of the firstmeta-photodiode 100 and the center of the third meta-photodiode 300.When four meta-photodiodes are arranged in a square shape in one pixelPX, the first spacing Sx and the second spacing Sy may be the same.Here, the first direction (X direction) or the second direction (Ydirection) may be a direction parallel to a direction of a side of eachpixel PX, respectively.

According to the example embodiment, the first spacing Sx and the secondspacing Sy may be selected so that the absorption spectra of the firstmeta-photodiode 100, the second meta-photodiode 200, and the thirdmeta-photodiode 300 remain substantially constant regardless of thechief ray angle of incident light. Then, the absorption spectra ofpixels located at the central portion of the pixel array 1100 and pixelslocated at the periphery of the pixel array 1100 may be uniform.

FIG. 7 is a table showing a comparison of color separation resultsaccording to a width of meta-photodiodes and a spacing betweenmeta-photodiodes with respect to different chief ray angles.

Referring to FIG. 7 , in Example Embodiment 1, the first meta-photodiode100, the second meta-photodiode 200, and the third meta-photodiode 300have a cylindrical shape and are arranged as shown in FIG. 5 . The firstmeta-photodiode 100 has a diameter of 120 nm, the second meta-photodiode200 has a diameter of 90 nm, and the third meta-photodiode 300 has adiameter of 70 nm. When a spacing between two adjacent meta-photodiodesis 220 nm, 180 nm, and 150 nm, at a chief ray angle of 0° and a chiefray angle of 30°, the absorption characteristics of the firstmeta-photodiode 100, the second meta-photodiode 200, and the thirdmeta-photodiode 300 with respect to red light, green light, and bluelight were compared. In addition, R Sum, G Sum, and B Sum representabsorption amounts for red light, green light, and blue light at a chiefray angle of 30° when the absorption amount for red light, green light,and blue light at a chief ray angle of 0° is 1.

As may be seen from FIG. 7 , as a spacing between two adjacentmeta-photodiodes decreases, the absorption characteristics of the firstmeta-photodiode 100, the second meta-photodiode 200, and the thirdmeta-photodiode 300 with respect to incident light incident at a chiefray angle of 0° and incident light incident at a chief ray angle of 30°become close to each other. When a spacing between two adjacentmeta-photodiodes is 150 nm, the absorption characteristics of the firstmeta-photodiode 100, the second meta-photodiode 200, and the thirdmeta-photodiode 300 with respect to incident light incident at a chiefray angle of 0° and incident light incident at a chief ray angle of 30°are most similar to each other.

Also, in Example Embodiment 2, the first meta-photodiode 100, the secondmeta-photodiode 200, and the third meta-photodiode 300 have acylindrical shape, and are arranged as shown in FIG. 5 . The firstmeta-photodiode 100 has a diameter of 136 nm, the second meta-photodiode200 has a diameter of 122 nm, and the third meta-photodiode 300 has adiameter of 104 nm. In Embodiment 2, referring to R Sum, G Sum, and BSum, as a spacing between two adjacent meta-photodiodes decreases,absorption characteristics of the first meta-photodiode 100, the secondmeta-photodiode 200, and the third meta-photodiode 300 with respect toincident light incident at a chief ray angle of 0° and incident lightincident at a chief ray angle of 30° are close to each other. Inaddition, when the spacing between two adjacent meta-photodiodes is 150nm, the absorption characteristics of the first meta-photodiode 100, thesecond meta-photodiode 200, and the third meta-photodiode 300 withrespect to incident light incident at a chief ray angle of 0° andincident light incident at a chief ray angle of 30° are most similar toeach other.

FIGS. 8A to 8C, 9A to 9C, 10A to 100, 11A to 110 and 12A to 12C aregraphs showing changes in absorption spectra of blue light, green light,and red light according to sizes of meta-photodiodes and a spacingbetween meta-photodiodes compared at different chief ray angles.

FIGS. 8A to 8C are graphs showing comparisons of absorption spectra ofthe third meta-photodiode 300, the second meta-photodiode 200, and thefirst meta-photodiode 100 with respect to incident light incident at achief ray angle of 0° and incident light incident at a chief ray angleof 30° when a spacing between two adjacent meta-photodiodes inEmbodiment 1 is 220 nm. FIGS. 9A to 9C are graphs for a case when thespacing between two adjacent meta-photodiodes in Embodiment 1 is 180 nm.Also, FIGS. 10A to 100 are graphs for a case when the spacing betweentwo adjacent meta-photodiodes in Embodiment 1 is 150 nm. Referring toFIGS. 7, 8A to 8C, 9A to 9C, 10A to 100 , it may be seen that, comparedto the case when the spacing between the meta-photodiodes is 180 nm, inthe case when the spacing between the meta-photodiodes is 150 nm, asignal difference between the incident light incident at a chief rayangle of 0° and the incident light incident at a chief ray angle of 30°is small. In addition, when the spacing between the meta-photodiodes is150 nm, positions of absorption spectrum peaks of the thirdmeta-photodiode 300, the second meta-photodiode 200, and the firstmeta-photodiode 100 with respect to incident light incident at a chiefray angle of 0° and incident light incident at a chief ray angle of 30°are almost identical.

FIGS. 11A to 11C are graphs showing comparisons of absorption spectra ofthe third meta-photodiode 300, the second meta-photodiode 200, and thefirst meta-photodiode 100 with respect to incident light incident at achief ray angle of and incident light incident at a chief ray angle of30° when a spacing between two adjacent meta-photodiodes in Embodiment 2is 220 nm. FIGS. 12A to 12C are graphs for a case when the spacingbetween two adjacent meta-photodiodes in Embodiment 2 is 150 nm.Referring to FIGS. 11A to 12C, when the spacing between two adjacentmeta-photodiodes is 150 nm, it may be seen that the absorption spectraof the third meta-photodiode 300, the second meta-photodiode 200, andthe first meta-photodiode 100 with respect to incident light incident ata chief ray angle of 0° and incident light incident at a chief ray angleof 30° are almost identical.

Accordingly, if the spacing between two adjacent meta-photodiodes issufficiently small, regardless of a width or diameter of the firstmeta-photodiode 100, the second meta-photodiode 200, and the thirdmeta-photodiode 300, absorption spectra of the first meta-photodiode100, the second meta-photodiode 200, and the third meta-photodiode 300with respect to incident light incident at chief ray angles differentfrom each other may be relatively uniformly maintained. For example, inone pixel PX, a spacing Sx between two meta-photodiodes adjacent in thefirst direction (X direction) among the first meta-photodiode 100, thesecond meta-photodiode 200, and the third meta-photodiode 300 may be 150nm or less, and may be equal to or greater than ½ of the sum of thewidths or diameters of two adjacent meta-photodiodes. In addition, inone pixel PX, a spacing Sy between two meta-photodiodes adjacent in thesecond direction (Y direction) may also be 150 nm or less, and may beequal to or greater than ½ of the sum of the widths or diameters of twoadjacent meta-photodiodes. However, the disclosure is not limited to onepixel PX, and as such, according to another example embodiment, in eachof the plurality of pixels in the pixel array 1100, a spacing Sx betweentwo meta-photodiodes adjacent in the first direction (X direction) amongthe first meta-photodiode 100, the second meta-photodiode 200, and thethird meta-photodiode 300 may be 150 nm or less, and may be equal to orgreater than ½ of the sum of the widths or diameters of two adjacentmeta-photodiodes. In addition, in each of the plurality of pixels in thepixel array 1100, a spacing Sy between two meta-photodiodes adjacent inthe second direction (Y direction) may also be 150 nm or less, and maybe equal to or greater than ½ of the sum of the widths or diameters oftwo adjacent meta-photodiodes.

Alternatively, in one pixel PX, the spacing Sx between twometa-photodiodes adjacent in the first direction (X direction) among thefirst meta-photodiode 100, the second meta-photodiode 200, and the thirdmeta-photodiode 300 may be equal to or less than ⅓ of a diffractionlimit determined by optical properties of an imaging optical system, forexample, the lens assembly 1910. Similarly, the spacing Sy between twometa-photodiodes adjacent in the second direction (Y direction) may beequal to or less than ⅓ of a diffraction limit determined by opticalproperties of an imaging optical system, for example, the lens assembly1910.

Alternatively, in one pixel PX, when the sum of widths or diameters inthe first direction (X direction) of two meta-photodiodes adjacent inthe first direction (X direction) among the first meta-photodiode 100,the second meta-photodiode 200, and the third meta-photodiode 300 is Wx,the spacing Sx between two meta-photodiodes adjacent in the firstdirection (X direction) may satisfy Wx/2+40 nm>Sx. In addition, when thesum of widths or diameters in the second direction (Y direction) of twometa-photodiodes adjacent in the second direction (Y direction) is Wy,the spacing Sy between two meta-photodiodes adjacent in the seconddirection (Y direction) may satisfy Wy/2+40 nm>Sy.

In one pixel PX, when the spacing between two adjacent meta-photodiodessatisfies the condition described above, the influence of a chief rayangle of incident light on the absorption spectra of the firstmeta-photodiode 100, the second meta-photodiode 200, and the thirdmeta-photodiode 300 may be greatly reduced. Accordingly, when designingthe pixel array 1100, there is no need to differently select sizes,heights, widths, spacings, etc. of the first meta-photodiode 100, thesecond meta-photodiode 200, and the third meta-photodiode 300 accordingto the position of a pixel PX on the pixel array 1100 in considerationof the chief ray angle of incident light.

In other words, referring to FIG. 5 , the arrangement form of the firstmeta-photodiode 100, the second meta-photodiode 200, and the thirdmeta-photodiode 300 arranged in the plurality of pixels PX at thecentral portion (C) of the pixel array 1100 may be the same as thearrangement form of the first meta-photodiode 100, the secondmeta-photodiode 200, and the third meta-photodiode 300 arranged in theplurality of pixels PX in the periphery (P) of the pixel array 1100.Here, the same arrangement form may denote that the structures, sizes,relative positions, and the like of the meta-photodiodes are the same.For example, in the central portion and the periphery of the pixel array1100, the widths or diameters, heights, structures, and materials of thefirst meta-photodiodes 100 may be the same as each other, the widths ordiameters, heights, structures, and materials of the secondmeta-photodiodes 200 may be the same as each other, and the widths ordiameters, heights, structures, and materials of the thirdmeta-photodiodes 300 may be the same as each other. In addition, in theplurality of pixels PX at the central portion and the periphery of thepixel array 1100, the spacing between the first meta-photodiode 100, thesecond meta-photodiode 200, and the third meta-photodiode 300 andrelative positions may be the same as each other.

As described with reference to FIG. 3 , the central portion of the pixelarray 1100 is a region where incident light is incident almostperpendicularly, and the periphery of the pixel array 1100 surrounds thecentral portion and is a region where incident light is obliquelyincident. In conclusion, in an entire region of the pixel array 1100according to the example embodiment, the first meta-photodiodes 100arranged in the plurality of pixels PX have the same structure, thesecond meta-photodiodes 200 arranged in the plurality of pixels PX havethe same structure, and the third meta-photodiodes 300 arranged in theplurality of pixels PX have the same structure, and, the firstmeta-photodiode 100, the second meta-photodiode 200, and the thirdmeta-photodiode 300 may have the same arrangement as each other in theplurality of pixels PX.

FIG. 13 is a plan view illustrating a structure of a pixel array 1100 ofan image sensor 1000 according to another example embodiment. Referringto FIG. 13 , the pixel array 1100 of the image sensor 1000 may furtherinclude isolation film 510 provided between adjacent pixels PX to reduceinterference between the pixels PX. The isolation film 510 may include alow refractive index material having a refractive index of 1 or more or2 or less. For example, the isolation film 510 may include air, SiO₂,Si₃N₄, or Al₂O₃.

FIGS. 14A to 14C, 15A to 15C and 16A to 16C are graphs showingcomparisons of changes in absorption spectra of blue light, green light,and red light according to a width of an isolation film between pixelswith respect to different chief ray angles. In FIGS. 14A to 14C, 15A to15C and 16A to 16C, when a diameter of the first meta-photodiode 100 is120 nm, a diameter of the second meta-photodiode 200 is 90 nm, and adiameter of the third meta-photodiode 300 is 70 nm and a spacing betweentwo adjacent meta-photodiodes in the pixel PX is 150 nm, at a chief rayangle of 0° and a chief ray angle of 30°, absorption characteristics ofthe first meta-photodiode 100, the second meta-photodiode 200, and thethird meta-photodiode 300, with respect to red light, green light, andblue light were compared.

First, FIGS. 14A to 14C show comparisons of the absorption spectra ofthe third meta-photodiode 300, the second meta-photodiode 200, and thefirst meta-photodiode 100 with respect to incident light incident at achief ray angle of 0° and incident light incident at a chief ray angleof 30° when the isolation film 510 is not present or when a width of theisolation film 510 is 0 nm. FIGS. 15A to 15C are graphs for a case whenthe isolation film 510 is air and the width Wair of the isolation film510 is 50 nm, and FIGS. 16A to 16C are graphs for a case when theisolation film 510 is air and the width Wair of the isolation film 510is 150 nm. Referring to FIGS. 14A to 14C, 15A to 15C and 16A to 16C,when the first meta-photodiode 100, the second meta-photodiode 200, andthe third meta-photodiode 300 are arranged in an area having a size lessthan a diffraction limit in one pixel PX and a spacing between adjacentmeta-photodiodes is 150 nm or less, it may be seen that even if a lowrefractive index isolation film 510 is provided between the pixels PX,the change in absorption spectrum according to the chief ray angle issmall.

FIG. 17 is a pixel arrangement of an image sensor according to acomparative example, and FIG. 18 is a graph showing efficiencies foreach color of the image sensor according to the comparative example.

The image sensor according to the comparative example has a pixelarrangement based on a Bayer pattern. Repeating units RU include twogreen sub-pixels, one red sub-pixel, and one blue sub-pixel,respectively. A width p0 of the repeating units RU is 0.6 μm, and acolor separation structure for separating light of a corresponding colorto be incident on each sub-pixel is provided.

Referring to FIG. 18 , the sensing efficiency of green light and bluelight is low compared to the sensing efficiency of red light, and abandwidth of the green light and blue light is also greater than that ofthe red light. Accordingly, the repeating unit RU according to thecomparative example has a greater pitch than the pixel PX according tothe example embodiment, but the efficiency of separating and sensingcolor is evaluated to be lower. Furthermore, in the pixel arrangementaccording to the comparative example, because the repeating unit RUtakes charge of colors of incident light by dividing into foursub-regions, resolution degradation may occur even in a signalprocessing process. For example, R and B signals are obtained at twosub-pixel spacings, G signals are obtained at √2* sub-pixel spacings,and R/G/B signal information in the sub-pixel at a position where thesignal is not obtained is obtained by inference with surroundinginformation. Accordingly, resolution degradation may occur byunder-sampling, and artifacts such as aliasing may occur in an imagerestoration process.

On the other hand, in the image sensor 1000 according to the exampleembodiment, because each of the pixels PX of a very small pitch mayseparate and detect color components, signal processing such as samplingis not required, the possibility of generating additional artifacts islow, and thus, high-resolution images may be obtained.

FIG. 19 is a perspective view illustrating a schematic structure of apixel array 1101 of an image sensor according to another exampleembodiment. Referring to FIG. 19 , the pixel array 1101 is differentfrom the pixel array 1100 described above in that the pixel array 1101further includes a plurality of lenses 600 facing the plurality ofpixels PX one-to-one. By the lenses 600, energy exchange betweenadjacent pixels may be blocked, and thus, light efficiency may beincreased.

In the above descriptions, it is illustrated that one pixel PX includesone first meta-photodiode 100 that absorbs red light, one secondmeta-photodiode 200 that absorbs green light, and two thirdmeta-photodiodes 300 that absorb blue light, but the disclosure is notlimited thereto, and various types and numbers of meta-photodiodes maybe utilized in the image sensor according to other example embodiments.

FIGS. 20 to 23 are plan views illustrating arrangements of various typesof meta-photodiodes provided in one pixel PX in each of the imagesensors according to other example embodiments.

Referring to FIG. 20 , each pixel PX in a pixel array 1102 may includeone first meta-photodiode 102 that selectively absorbs red light, aplurality of second meta-photodiodes 202 that selectively absorbs greenlight, and a plurality of third meta-photodiodes 302 that selectivelyabsorbs blue light. The first meta-photodiode 102 may be provided at thecenter of the pixel PX, and four second meta-photodiodes 202 and fourthird meta-photodiodes 302 may be arranged to surround the firstmeta-photodiode 102 in a rectangular shape. For example, four secondmeta-photodiodes 202 may be provided at vertices of the rectangle, andfour third meta-photodiodes 302 may be provided at the centers of thesides of the rectangle. Unlike the pixel array 1102 shown in FIG. 20 ,positions of the second meta-photodiode 202 and the thirdmeta-photodiode 302 may be changed with each other.

Even in each pixel PX in the pixel array 1102 shown in FIG. 20 , aspacing between two adjacent meta-photodiodes may satisfy the conditiondescribed above. For example, spacing S1 x between a first secondmeta-photodiode 202 and a first third meta-photodiode 302 adjacent inthe first direction, spacing S2 x between a second secondmeta-photodiode 202 and the first third meta-photodiode 302 adjacent inthe first direction, spacing S1 y between the second secondmeta-photodiode 202 and a second third meta-photodiode 302 adjacent inthe second direction and spacing S2 y between the a third secondmeta-photodiode 202 and the second third meta-photodiode 302 adjacent inthe second direction may be 150 nm or less, or ⅓ or less of adiffraction limit determined by optical properties of an imaging opticalsystem. Alternatively, in one pixel PX, when a spacing between thesecond meta-photodiode 202 and the third meta-photodiode 302 is S, and asum of the widths of the second meta-photodiode 202 and the thirdmeta-photodiode 302 is W, Equation, W/2+40 nm>S, may be satisfied.

Referring to FIG. 21 , each pixel PX in the pixel array 1103 may includetwo first meta-photodiodes 103 that selectively absorb red light, twosecond meta-photodiodes 203 that selectively absorb green light, andfive third meta-photodiodes 303 that selectively absorb blue light. Thetwo first meta-photodiodes 103 may be provided at the center of twoopposite sides of a rectangle, the two second meta-photodiodes 203 maybe provided at the centers of the other two opposite sides of therectangle, and one of the third meta-photodiodes 303 may be provided atthe center of the rectangle, and the remaining four thirdmeta-photodiodes 303 may be provided at vertices of the rectangle. Evenin this case, the spacing between two adjacent meta-photodiodes amongthe first meta-photodiode 103, the second meta-photodiode 203, and thethird meta-photodiode 303 may satisfy the conditions described above.

In FIGS. 20 and 21 , the sum of the numbers of the firstmeta-photodiodes 102 and 103, the second meta-photodiodes 202 and 203,and the third meta-photodiodes 302 and 303 is nine, and the ninemeta-photodiodes may be arranged in the form of a 3×3 array. Inaddition, the nine meta-photodiodes are arranged in rectangle, forexample, a square unit lattice form. However, the example embodiment isnot necessarily limited thereto.

Referring to FIG. 22 , in a pixel array 1104, the pixels PX may bearranged in a hexagonal lattice shape. One pixel PX may include onefirst meta-photodiode 104 that selectively absorbs red light, threesecond meta-photodiodes 204 that selectively absorb green light, andthree third meta-photodiodes 304 that selectively absorb blue light. Thefirst meta-photodiode 104 may be provided at the center of a hexagon,and the second meta-photodiode 204 and the third meta-photodiode 304 maybe alternately provided at each vertex of the hexagon. Two pixels PXprovided adjacent to each other to share one side may share one secondmeta-photodiode 204 and one third meta-photodiode 304 provided at bothvertices of the shared side. Accordingly, one second meta-photodiode 204and one third meta-photodiode 304 may be shared by three surroundingpixels PX. Even in this case, the spacing S between the adjacent secondmeta-photodiode 204 and the third meta-photodiode 304 may satisfy theconditions described above.

Also, referring to FIG. 23 , a pixel PX of a pixel array 1105 mayinclude a first meta-photodiode 105 that selectively absorbs red light,a second meta-photodiode 205 that selectively absorbs green light, and athird meta-photodiode 305 that selectively absorbs blue light, andadditionally may further include a fourth meta-photodiode 400 thatselectively absorbs light of an infrared wavelength band. One fourthmeta-photodiode 400 may be provided in the center, and four firstmeta-photodiodes 105, four second meta-photodiodes 205, and four thirdmeta-photodiodes 305 may be provided in the form of surrounding thefourth meta-photodiode 400. The fourth meta-photodiode 400 may have thelargest diameter, for example, greater than 100 nm. The diameter of thefourth meta-photodiode 400 may be set in a range of about 100 nm toabout 200 nm.

In this way, in addition to color information about an object, depthinformation may further be obtained from an image sensor furtherincluding a meta-photodiode that selectively absorbs infrared wavelengthbands in addition to a meta-photodiode that selectively absorbs R, G,and B colors. For example, a camera module including the image sensormay further include an infrared light source irradiating infrared lightto an object, and infrared information sensed by the image sensor may beutilized to obtain depth information of the object. That is, depthinformation of the object may be obtained based on infrared informationsensed by the image sensor, and color information of the object may beobtained based on sensed visible light information. Also, 3D imageinformation may be obtained by combining color information and depthinformation.

FIG. 24 is a cross-sectional view illustrating a structure of a pixelarray 1106 of the image sensor 1000 according to another exampleembodiment. Referring to FIG. 24 , the pixel array 1106 of the imagesensor 1000 may further include an optical plate 620 provided to face alight incident surface of the plurality of pixels PX. The optical plate620 may be configured to change a traveling direction of incident lightto be perpendicular to the light incident surface of the plurality ofpixels PX. For example, in a central portion 1106C of the pixel array1106 through which incident light is vertically incident, the opticalplate 620 may transmit the incident light as it is without changing thetraveling direction of the incident light. On the other hand, in aperiphery 1106P of the pixel array 1106, where the incident lightobliquely enters, the optical plate 620 may change the travelingdirection of the incident light to be perpendicular to the lightincident surface of the pixel PX.

Because incident light is perpendicularly incident to the pixel PX ofthe central portion 1106C and the periphery 1106P of the pixel array1106 according to the example embodiment, the spacing Sx between twoadjacent meta-photodiodes among the first meta-photodiode 100, thesecond photodiode 200, and the third meta-photodiode 300 may not satisfythe condition described above. In other words, when the optical plate620 is used, the spacing Sx between two adjacent meta-photodiodes maybe, for example, 150 nm or more. In addition, because incident light isvertically incident to the pixel PX of the central portion 1106C and theperiphery 1106P of the pixel array 1106, in the central portion 1106Cand the periphery 1106P of the pixel array 1106, the arrangement form ofthe first meta-photodiode 100, the second meta-photodiode 200, and thethird meta-photodiode 300 arranged in the plurality of pixels PX may bethe same.

The optical plate 620 may be, for example, a digital micro-lens arrayincluding a plurality of digital micro-lenses arranged in twodimensions. When the optical plate 620 is a digital micro-lens array,the optical plate 620 may change the traveling direction of incidentlight vertically while focusing the incident light to each pixel PX. Tothis end, the optical plate 620 may have a nano-pattern structurecapable of focusing incident light. The nano-pattern structure mayinclude a plurality of nano-structures that change a phase of incidentlight differently according to an incident position of the incidentlight in each pixel PX. The shape, size (width, height), spacing,arrangement form, and the like of the plurality of nano-structures maybe determined so that light, immediately after passing through theoptical plate 620, has a preset phase profile. A traveling direction andfocal length of the light passing through the optical plate 620 may bedetermined according to the phase profile.

FIG. 25 is a plan view illustrating a nano-pattern structure of anoptical plate 620 positioned in a central portion of a pixel array.Referring to FIG. 25 , a nano-structure NP having a nano-patternstructure may be a nano-column having a cross-sectional diameter of asub-wavelength dimension. When incident light is visible light, thecross-sectional diameter of the nano-structure NP may have a dimension,for example, 400 nm, 300 nm, 200 nm, or less. A height of thenano-structure NP may be in a range from about 500 nm to about 1500 nm,and the height may be greater than the cross-sectional diameter.

The nano-structure NP may include a material having a relatively highrefractive index and a relatively low absorption in the visible lightband compared to surrounding materials. For example, the nano-structureNP may include c-Si, p-Si, a-Si and a Group III-V compound semiconductor(GaP, GaN, GaAs, etc.), SiC, TiO₂, SiN₃, ZnS, ZnSe, Si₃N₄ and/orcombinations thereof. The periphery of the nano-structure NP may befilled with a dielectric material having a relatively low refractiveindex than that of the nano-structure NP and having a relatively lowabsorptivity in the visible light band. For example, the periphery ofthe nano-structure NP may be filled with air, SiO₂, Si₃N₄, Al₂O₃, etc.The nano-structure NP having a refractive index difference from that ofthe surrounding material may change the phase of light passing throughthe nano-structure NP. This is due to a phase delay caused by a shapedimension of a sub-wavelength of the nano-structure NP, and the degreeof the phase delay is determined by a detailed shape dimension andarrangement shape of the nano-structure NP.

The nano-pattern structure of the optical plate 620 shown in FIG. 25 maybe a unit pattern forming one digital micro-lens of the digitalmicro-lens array. The plurality of digital micro-lenses may correspondto the plurality of pixels PX on a one-to-one basis, and may be providedto face the corresponding pixels PX. Accordingly, the plurality ofnano-pattern structures shown in FIG. 25 may be two-dimensionallyarranged in the optical plate 620.

FIG. 26 is a graph showing a phase profile of light immediately afterpassing through one digital micro-lens of the optical plate 620 in thecentral portion of the pixel array. Referring to FIG. 26 , lightimmediately after passing through one digital micro-lens of the opticalplate 620 may have a phase profile that is the greatest at the center ofthe pixel PX corresponding to the digital micro-lens and decreases as itmoves away from the center of the pixel PX in the first direction (Xdirection). In the central portion 1106C of the pixel array 1106 where achief ray angle of incident light is 0 degree, because the optical plate620 does not need to change the traveling direction of the incidentlight, the nano-pattern structure of the optical plate 620 may beconfigured to implement a phase profile in the form of a symmetricalconvex curved surface as shown in FIG. 26 . In addition, thenano-pattern structure of the optical plate 620 may be configured toimplement a phase profile in the form of a symmetrical convex curvedsurface not only in the first direction (X direction) but also in thesecond direction (Y direction).

Referring to FIG. 25 , to implement the phase profile as above, theplurality of nano-structures NP in each digital micro-lens of theoptical plate 620 may be arranged in a symmetrical form in the firstdirection and the second direction with respect to the center of eachdigital micro-lens. In particular, the nano-structures NPs arranged in acentral region of each digital micro-lens may have the largest diameterso that the largest phase delay occurs in the central region of eachdigital micro-lens, and the diameter of the nano-structure NP maygradually decrease as it moves away from the central region of eachdigital micro-lens. For example, the nano-structures NPs provided atfour vertices of each digital micro-lens may have the smallest diameter.

FIG. 27 is a plan view illustrating a nano-pattern structure of anoptical plate 620 positioned at a periphery of a pixel array. FIG. 28 isa graph showing an example phase profile of light immediately afterpassing through one digital micro-lens of the optical plate 620 at aperiphery of a pixel array.

Referring to FIG. 27 , nano-structures NPs having the largest diameterare provided away from the central portion of each digital micro-lens.For example, diameters of the nano-structures NPs may gradually increasein the first direction (X direction).

Referring to FIG. 28 , light immediately after passing through onedigital micro-lens of the optical plate 620 may have a phase profile inwhich a convex curved phase profile is added to an inclined linear phaseprofile LP. The convex curved phase profile may serve to focus incidentlight, and the inclined linear phase profile LP may serve to deflect atraveling direction of incident light. The inclined linear phase profileLP may have a shape in which a phase linearly increases toward a centralportion 1106C of the pixel array 1106 or a central portion of theoptical plate 620. A slope of the inclined linear phase profile LP maybe determined according to a chief ray angle of incident light. Thechief ray angle increases as it moves away from the central portion1106C of the pixel array 1106 or the central portion of the opticalplate 620. Accordingly, the slope of the inclined linear phase profileLP may increase as the increase in a distance from the central portion1106C of the pixel array 1106 or the central portion of the opticalplate 620. For example, the slope of the inclined linear phase profileLP may be proportional to a sine value of an angle of incidence ofincident light incident to the optical plate 620, that is, a sine valuesin(CRA) of the chief ray angle.

According to another example embodiment, the optical plate 620 mayinclude, for example, a digital deflector. The digital deflector mayinclude a plurality of deflector elements corresponding one-to-one tothe plurality of pixels PX of the pixel array 1106. The digitaldeflector may include a plurality of nano-structures NPs as thenano-pattern structures shown in FIGS. 25 and 27 . Unlike the digitalmicro-lens array, the digital deflector may not have a convex phaseprofile. For example, the digital deflector may include a nano-patternstructure configured to have only a linear phase profile while removinga convex curved phase profile from the phase profile shown in FIGS. 26and 28 .

The pixel array 1106 of the image sensor 1000 may further include aspacer layer 610 provided between the plurality of pixels PX and theoptical plate 620. The spacer layer 610 may support the optical plate620. In addition, when the optical plate 620 is a digital micro-lensarray, the spacer layer 610 may provide a gap for securing a focallength of the micro-lens. The spacer layer 610 may include alow-refractive-index material having transparency with respect toincident light, for example, SiO₂, Si₃N₄, or Al₂O₃. However, when afocal length of the micro-lens is sufficiently short or when the opticalplate 620 is a digital deflector, the spacer layer 610 may be omitted.

FIG. 29 is a cross-sectional view illustrating a structure of a pixelarray 1107 of an image sensor according to another example embodiment.Referring to FIG. 29 , the pixel array 1107 is different from the pixelarray 1106 in that the pixel array 1107 further includes a plurality oflenses 600 facing the plurality of pixels PX on a one-to-one basis. Theplurality of lenses 600 may be provided between the plurality of pixelsPX and the optical plate 620, in particular, between the plurality ofpixels PX and the spacer layer 610.

Although it has been described that the pixels PX included in the imagesensor 1000 described above sense R, G, and B colors, the pixels PX maybe modified to include a meta-photodiode capable of distinguishing anddetecting light of different wavelength bands. For example, in order toobtain a hyperspectral image in an ultraviolet to infrared wavelengthrange, a plurality of meta-photodiodes having different cross-sectionaldiameters, for example 4, 8, or 16 meta-photodiodes, may be included inone pixel. A width of a pixel including the meta-photodiodes may be setto be less than λm, which is the shortest wavelength among thewavelength bands. This is a value corresponding to a diffraction limitwhen the F-number of the imaging optical system is assumed to be about1.0. A minimum value of a pixel width may be set to suit the diameterand number of meta-photodiodes included in one pixel.

In addition, the pixels PX included in the image sensor 1000 may bemodified to include meta-photodiodes for sensing cyan/magenta/yellowcolors, or may be configured to sense other multi-colors.

The image sensor 1000 according to the example embodiment may constitutea camera module together with module lenses having various performances,and may be utilized in various electronic apparatuses.

FIG. 30 is a block diagram illustrating an example of an electronicapparatus ED01 including the image sensor 1000. Referring to FIG. 30 ,in a network environment ED00, the electronic apparatus ED01 maycommunicate with another electronic apparatus ED02 through a firstnetwork ED98 (a short-range wireless communication network, etc.) or maycommunicate with another electronic apparatus ED04 and/or a server ED08through a second network ED99 (a remote wireless communication network,etc.). The electronic apparatus ED01 may communicate with the electronicapparatus ED04 through the server ED08. The electronic apparatus ED01may include a processor ED20, a memory ED30, an input device ED50, anaudio output device ED55, a display device ED60, an audio module ED70, asensor module ED76, an interface ED77, a haptic module ED79, a cameramodule ED80, a power management module ED88, a battery ED89, acommunication module ED90, a subscriber identification module ED96,and/or an antenna module ED97. In the electronic apparatus ED01, some ofthese components (e.g., the display device ED60) may be omitted or othercomponents may be added. Some of these components may be implemented asone integrated circuit. For example, the sensor module ED76 (afingerprint sensor, an iris sensor, an illuminance sensor, etc.) may beimplemented by being embedded in the display device ED60 (a display,etc.).

The processor ED20 may control one or a plurality of other components(hardware, software components, etc.) of the electronic apparatus ED01connected to the processor ED20 by executing software (e.g., a programED40), and may perform various data processing or operations. As a partof data processing or computations, the processor ED20 may load commandsand/or data received from other components (the sensor module ED76 andthe communication module ED90, etc.) into a volatile memory ED32 and mayprocess commands and/or data stored in the volatile memory ED32, and theresulting data may be stored in a non-volatile memory ED34. Theprocessor ED20 may include a main processor ED21 (a central processingunit, an application processor, etc.) and an auxiliary processor ED23 (agraphics processing unit, an image signal processor, a sensor hubprocessor, a communication processor, etc.) that may be operatedindependently or together with the main processor ED21. The auxiliaryprocessor ED23 may use less power than the main processor ED21 and mayperform a specialized function.

The auxiliary processor ED23 is configured to replace the main processorED21 while the main processor ED21 is in the inactive state (sleepstate) or the main processor ED21 while the main processor ED21 is inthe active state (the application execution state). Together with theprocessor ED21, functions and/or states related to some of thecomponents of the electronic device ED01 (the display device ED60, thesensor module ED76, the communication module ED90, etc.) may becontrolled. The auxiliary processor ED23 (an image signal processor, acommunication processor, etc.) may be implemented as a part of otherfunctionally related components (the camera module ED80, thecommunication module ED90, etc.).

The memory ED30 may store various pieces of data required by componentsof the electronic device ED01 (such as the processor ED20 and the sensormodule ED76). The data may include, for example, input data and/oroutput data for software (such as the program ED40) and instructionsrelated thereto. The memory ED30 may include the volatile memory ED32and/or the nonvolatile memory ED34.

The program ED40 may be stored as software in the memory ED30 and mayinclude an operating system ED42, middleware ED44, and/or an applicationED46.

The input device ED50 may receive a command and/or data to be used in acomponent (such as, the processor ED20) of the electronic apparatus ED01from the outside of the electronic apparatus ED01 (e.g., a user). Theinput device ED50 may include a microphone, a mouse, a keyboard, and/ora digital pen (such as, a stylus pen).

The audio output device ED55 may output a sound signal to the outside ofthe electronic apparatus ED01. The audio output device ED55 may includea speaker and/or a receiver. The speaker may be used for generalpurposes, such as, multimedia playback or recording playback, and thereceiver may be used to receive an incoming call. The receiver may beincorporated as a part of the speaker or may be implemented as anindependent separate device.

The display device ED60 may visually provide information to the outsideof the electronic apparatus ED01. The display device ED60 may include acontrol circuit for controlling a display, a hologram device, or aprojector, and a corresponding device. The display device ED60 mayinclude touch circuitry configured to sense a touch, and/or sensorcircuitry configured to measure the intensity of force generated by thetouch (a pressure sensor, etc.).

The audio module ED70 may convert sound into an electric signal or,conversely, convert an electric signal into sound. The audio module ED70may obtain sound through the input device ED50 or output sound through aspeaker and/or headphones of the audio output device ED55 and/or anotherelectronic apparatus (the electronic apparatus ED02, etc.) directly orwirelessly connected to the electronic apparatus ED01.

The sensor module ED76 may detect an operating state (power,temperature, etc.) of the electronic apparatus ED01 or an externalenvironmental state (a user state, etc.), and generate an electricalsignal and/or data value corresponding to the sensed state. The sensormodule ED76 may include a gesture sensor, a gyro sensor, a barometricpressure sensor, a magnetic sensor, an acceleration sensor, a gripsensor, a proximity sensor, a color sensor, an infrared (IR) sensor, abiometric sensor, a temperature sensor, a humidity sensor, and/or anilluminance sensor.

The interface ED77 may support one or more designated protocols that maybe used by the electronic apparatus ED01 to directly or wirelesslyconnect with another electronic apparatus (the electronic apparatusED02, etc.). The interface ED77 may include a High Definition MultimediaInterface (HDMI), a Universal Serial Bus (USB) interface, an SD cardinterface, and/or an audio interface.

A connection terminal ED78 may include a connector through which theelectronic apparatus ED01 may be physically connected to anotherelectronic apparatus (the electronic apparatus ED02, etc.). Theconnection terminal ED78 may include an HDMI connector, a USB connector,an SD card connector, and/or an audio connector (a headphones connector,etc.).

The haptic module ED79 may convert an electrical signal into amechanical stimulus (vibration, movement, etc.) or an electricalstimulus that may be perceived by the user through tactile orkinesthetic sense. The haptic module ED79 may include a motor, apiezoelectric element, and/or an electrical stimulation device.

The camera module ED80 may capture still images and moving images. Thecamera module ED80 may include a lens assembly including one or morelenses, the image sensor 1000 of FIG. 1 , image signal processors,and/or flashes. The lens assembly included in the camera module ED80 maycollect light emitted from an object, an image of which is to becaptured.

The power management module ED88 may manage power supplied to theelectronic apparatus ED01. The power management module ED88 may beimplemented as part of a Power Management Integrated Circuit (PMIC).

The battery ED89 may supply power to components of the electronicapparatus ED01. The battery ED89 may include a non-rechargeable primarycell, a rechargeable secondary cell, and/or a fuel cell.

The communication module ED90 may support the establishment of a direct(wired) communication channel and/or a wireless communication channelbetween the electronic apparatus ED01 and other electronic apparatuses(the electronic device ED02, the electronic device ED04, the serverED08, etc.) and performance of communications through the establishedcommunication channel. The communication module ED90 may include one ora plurality of communication processors that operate independently fromthe processor ED20 (an application processor, etc.) and support directcommunication and/or wireless communication. The communication moduleED90 may include a wireless communication module ED92 (a cellularcommunication module, a short-range wireless communication module, and aGlobal Navigation Satellite System (GNSS) communication module, etc.)and/or a wired communication module ED94 (a Local Area Network (LAN)communication module, a power line communication module, etc.). Amongthese communication modules, a corresponding communication module maycommunicate with other electronic apparatuses through the first networkED98 (a short-range communication network, such as Bluetooth, WiFiDirect, or Infrared Data Association (IrDA)) or the second network ED99(a telecommunication network, such as a cellular network, the Internet,or a computer network, such as a LAN, a wide area network (WAN), etc.).The various types of communication modules may be integrated into onecomponent (a single chip, etc.) or implemented as a plurality ofcomponents (plural chips) separate from each other. The wirelesscommunication module ED92 may identify and authenticate the electronicapparatus ED01 within a communication network, such as the first networkED98 and/or the second network ED99, by using subscriber information(such as, an International Mobile Subscriber Identifier (IMSI)) storedin a subscriber identification module ED96.

The antenna module ED97 may transmit or receive signals and/or power toand from the outside (other electronic devices, etc.). An antenna mayinclude a radiator having a conductive pattern formed on a substrate (aprinted circuit board (PCB), etc.). The antenna module ED97 may includeone or a plurality of antennas. When a plurality of antennas areincluded in the antenna module ED97, an antenna suitable for acommunication method used in a communication network, such as the firstnetwork ED98 and/or the second network ED99, from among the plurality ofantennas may be selected by the communication module ED90. Signalsand/or power may be transmitted or received between the communicationmodule ED90 and another electronic apparatus through the selectedantenna. In addition to the antenna, other components (a radio-frequencyintegrated circuit (RFIC), etc.) may be included as part of the antennamodule ED97.

Some of the components, between peripheral devices, may be connected toeach other through communication methods (a bus, General Purpose Inputand Output (GPIO), Serial Peripheral Interface (SPI), Mobile IndustryProcessor Interface (MIPI), etc.) and signals (commands, data, etc.) maybe interchangeable.

Commands or data may be transmitted or received between the electronicapparatus ED01 and an external electronic apparatus (the electronicapparatus ED04) through the server ED08 connected to the second networkED99. The electronic apparatuses ED02 and ED04 may be the same type asor different types from the electronic apparatus ED01. All or part ofthe operations executed by the electronic apparatus ED01 may be executedby one or more of the electronic apparatuses ED02 and ED04 and theserver ED08. For example, when the electronic apparatus ED01 needs toperform a function or service, the electronic apparatus ED01 may requestone or more other electronic devices to perform part or all of thefunction or service instead of executing the function or service itself.One or more other electronic apparatuses receiving the request mayexecute an additional function or service related to the request, andtransmit a result of the execution to the electronic apparatus ED01. Tothis end, cloud computing, distributed computing, and/or client-servercomputing technologies may be used.

FIG. 31 is a block diagram illustrating a camera module ED80 included inthe electronic apparatus ED01 of FIG. 30 . Referring to FIG. 31 , thecamera module ED80 may include a lens assembly 1110, a flash 1120, animage sensor 1000, an image stabilizer 1140, a memory 1150 (a buffermemory, etc.), and/or an image signal processor 1160. The lens assembly1110 may collect light emitted from an object to be imaged. The cameramodule ED80 may include a plurality of lens assemblies 1110, and, inthis case, the camera module ED80 may be a dual camera, a 360° camera,or a spherical camera. Some of the plurality of lens assemblies 1110 mayhave the same lens property (an angle of view, a focal length, an autofocus, an F-number, an optical zoom, etc.) or may have different lensproperties. The lens assembly 1110 may include a wide-angle lens or atelephoto lens.

The flash 1120 may emit light to be used to enhance light emitted orreflected from an object. The flash 1120 may emit visible light orinfrared light. The flash 1120 may include one or a plurality oflight-emitting diodes (a Red-Green-Blue (RGB) LED, a White LED, anInfrared LED, an Ultraviolet LED, etc.), and/or a Xenon Lamp. The imagesensor 1000 may be the image sensor 1000 described with reference toFIG. 1 , and may obtain an image corresponding to the object byconverting light emitted or reflected from the object and transmittedthrough the lens assembly 1110 into an electrical signal.

The image sensor 1000 may be the image sensor 1000 of FIG. 1 describedabove, and the type and arrangement of meta-photodiodes included in thepixel PX provided in the image sensor 1000 may have the form describedwith reference to FIGS. 5 and 20 to 23 , or a combination or modifiedform thereof. A plurality of pixels included in the image sensor 1000may have a small pixel width, for example, a width less than thediffraction limit. The width p of each of the plurality of pixelsprovided in the image sensor 1000 may satisfy the following condition:

p<λ·F.

Here, F is the F-number of the lens assembly 1110, and λ is the centerwavelength of a blue wavelength band.

The image stabilizer 1140 may move one or a plurality of lenses or theimage sensor 1000 included in the lens assembly 1110 in a specificdirection in response to the movement of the camera module ED80 or theelectronic apparatus ED01 including the camera module ED80, or maycompensate for a negative influence due to movement by controlling(adjustment of read-out timing, etc.) operating characteristics of theimage sensor 1000. The image stabilizer 1140 may detect the movement ofthe camera module ED80 or the electronic apparatus ED01 by using a gyrosensor (not shown) or an acceleration sensor (not shown) provided insideor outside the camera module ED80. The image stabilizer 1140 may beoptically implemented.

The memory 1150 may store some or all of image data acquired by theimage sensor 1000 for the next image processing operation. For example,when a plurality of images are acquired at a high speed, the acquiredoriginal data (Bayer-Patterned data, high-resolution data, etc.) isstored in the memory 1150, and only a low-resolution image is displayed,and then, may be used to transmit the original data of the selected(user selection, etc.) image to the image signal processor 1160. Thememory 1150 may be integrated into the memory ED30 of the electronicapparatus ED01 or may be configured as a separate memory operatedindependently.

The image signal processor 1160 may perform image processing on imagesacquired by the image sensor 1000 or image data stored in the memory1150. Image processing may include depth map generation, threedimensional (3D) modeling, panorama generation, feature pointextraction, image synthesis, and/or image compensation (noise reduction,resolution adjustment, brightness adjustment, blurring, sharpening,softening, etc.). The image signal processor 1160 may perform control(exposure time control, readout timing control, etc.) on components (theimage sensor 1000, etc.) included in the camera module ED80. The imageprocessed by the image signal processor 1160 may be stored back in thememory 1150 for further processing or provided to external components ofthe camera module ED80 (the memory ED30, the display device ED60, theelectronic apparatus ED02, the electronic apparatus ED04, the serverED08, etc.). The image signal processor 1160 may be integrated into theprocessor ED20 or configured as a separate processor operatedindependently from the processor ED20. When the image signal processor1160 is configured as a processor separate from the processor ED20, animage processed by the image signal processor 1160 may be displayed onthe display device ED60 after additional image processing by theprocessor ED20.

As illustrated in FIG. 13 , when the image sensor 1000 includes ameta-photodiode that selectively absorbs infrared wavelength band andmeta-photodiodes that selectively absorb red light, green light, andblue light separately, the image signal processor 1160 may process aninfrared signal and a visible light signal acquired from the imagesensor 1000 together. The image signal processor 1160 may obtain a depthimage of an object by processing an infrared signal, obtain a colorimage of the object from a visible light signal, and provide athree-dimensional image of the object by combining the depth image withthe color image. The image signal processor 1160 may also computeinformation on temperature or moisture of an object from the infraredsignal, and provide a temperature distribution and moisture distributionimage that is combined with a two-dimensional image (color image) of theobject.

The electronic apparatus ED01 may further include one or more additionalcamera modules each having different properties or functions. Such acamera module may also include a configuration similar to that of thecamera module ED80 of FIG. 31 , and an image sensor provided therein mayinclude one or a plurality of sensors selected from image sensors havingdifferent properties, such as a Charged Coupled Device (CCD) sensorand/or a Complementary Metal Oxide Semiconductor (CMOS) sensor, an RGBsensor, a black and white (BW) sensor, an IR sensor, or a UV sensor. Inthis case, one of the plurality of camera modules ED80 may be awide-angle camera and the other may be a telephoto camera. Similarly,one of the plurality of camera modules ED80 may be a front camera andthe other may be a rear camera.

The image sensor 1000 according to embodiments may be applied to amobile phone or smart phone 1200 shown in FIG. 32 , a tablet or smarttablet 1300 shown in FIG. 33 , and a digital camera or camcorder 1400shown in FIG. 34 , a notebook computer 1500 shown in FIG. 35 , or atelevision or smart television 1600 shown in FIG. 36 . For example, thesmart phone 1200 or the smart tablet 1300 may include a plurality ofhigh-resolution cameras each having a high-resolution image sensormounted thereon. The high-resolution cameras may be used to extractdepth information of objects in an image, adjust out-focusing of animage, or automatically identify objects in an image.

In addition, the image sensor 1000 may be applied to a smartrefrigerator 1700 shown in FIG. 37 , a security camera 1800 shown inFIG. 38 , a robot 1900 shown in FIG. 39 , a medical camera 2000 shown inFIG. 40 , etc. For example, the smart refrigerator 1700 mayautomatically recognize food in the refrigerator by using an imagesensor, and inform the user of the presence of specific food, the typeof food put in or take out, and the like through a smartphone. Thesecurity camera 1800 may provide an ultra-high-resolution image and mayrecognize an object or a person in an image even in a dark environmentby using high sensitivity. The robot 1900 may provide a high-resolutionimage by being input at a disaster or industrial site that cannot bedirectly accessed by a person. The medical camera 2000 may provide ahigh-resolution image for diagnosis or surgery, and may dynamicallyadjust a field of view.

Also, the image sensor 1000 may be applied to a vehicle 2100 as shown inFIG. 41 . The vehicle 2100 may include a plurality of vehicle cameras2110, 2120, 2130, and 2140 provided in various positions. Each of thevehicle cameras 2110, 2120, 2130, and 2140 may include an image sensoraccording to an example embodiment. The vehicle 2100 may provide adriver with various information about an interior or surroundings of thevehicle 2100 by using the plurality of vehicle cameras 2110, 2120, 2130,and 2140, and provide information necessary for autonomous driving byautomatically recognizing objects or people in the image.

In the image sensor according to the example embodiment, each pixelhaving a small width less than a diffraction limit may detect light of aplurality of types of wavelength bands separately. The image sensoraccording to the example embodiment may exhibit high luminous efficiencyby not using components such as a color separation element and a colorfilter.

Pixels of the image sensor according to the example embodiment may havesubstantially uniform absorption spectra in a central portion and aperiphery at which a chief ray angers of incident light are different.Accordingly, in the image sensor according to the example embodiment,the pixel structure may be the same in the central portion and theperiphery.

The image sensor according to the example embodiment may be used as amulti-color sensor, a multi-wavelength sensor, a hyper-spectral sensor,and may be used as a 3D image sensor that provides both a color imageand a depth image. The image sensor according to the example embodimentmay be may be applied as a high resolution camera module to be utilizedin various electronic devices.

It should be understood that embodiments described herein should beconsidered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other example embodiments. While one or more embodimentshave been described with reference to the figures, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeas defined by the following claims.

What is claimed is:
 1. An image sensor comprising: a pixel arraycomprising a plurality of two-dimensionally arranged pixels, whereineach of the plurality of pixels comprises: a first meta-photodiodeconfigured to selectively absorb light of a first wavelength band; asecond meta-photodiode configured to selectively absorb light of asecond wavelength band different from the first wavelength band; and athird meta-photodiode configured to selectively absorb light of a thirdwavelength band different from the first wavelength band and secondwavelength band, wherein, the first meta-photodiode, the secondmeta-photodiode, and the third meta-photodiode are arranged in an areahaving a size equal to or less than a diffraction limit, wherein thefirst meta-photodiode, the second meta-photodiode, and the thirdmeta-photodiode of one or more first pixels in a central portion of thepixel array, among the plurality of pixels, are arranged in a same formas the first meta-photodiode, the second meta-photodiode, and the thirdmeta-photodiode of one or more second pixels in a periphery of the pixelarray, among the plurality of pixels.
 2. The image sensor of claim 1,wherein, in the central portion and the periphery of the pixel array,the first meta-photodiodes arranged in the plurality of pixels have asame first structure, the second meta-photodiodes have a same secondstructure, and the third meta-photodiodes have a same third structure.3. The image sensor of claim 1, wherein, in each of the plurality ofpixels, the following condition is satisfied: W/2+40 nm>S, where S is aspacing between two meta-photodiodes adjacent in a first direction amongthe first meta-photodiode, the second meta-photodiode, and the thirdmeta-photodiode and W is a sum of widths of the two adjacentmeta-photodiodes.
 4. The image sensor of claim 1, wherein, in each ofthe plurality of pixels, a spacing between two meta-photodiodes adjacentin a first direction among the first meta-photodiode, the secondmeta-photodiode, and the third meta-photodiode is about 150 nm or less,and is at least ½ of a sum of widths of the two adjacentmeta-photodiodes.
 5. The image sensor of claim 1, wherein, in each ofthe plurality of pixels, a spacing between two meta-photodiodes adjacentin a first direction among the first meta-photodiode, the secondmeta-photodiode, and the third meta-photodiode is ⅓ or less of thediffraction limit.
 6. The image sensor of claim 1, wherein the centralportion of the pixel array is a first area in which incident light isvertically incident, and the periphery of the pixel array surrounds thecentral portion and is a second area in which incident light isobliquely incident.
 7. The image sensor of claim 1, wherein the pixelarray further comprises: an optical plate arranged to face lightincident surfaces of the plurality of pixels and configured to change atraveling direction of incident light to be perpendicular to the lightincident surfaces of the plurality of pixels.
 8. The image sensor ofclaim 7, wherein the optical plate comprises a digital micro-lens arrayor a digital deflector.
 9. The image sensor of claim 1, wherein each ofthe first meta-photodiode, the second meta-photodiode, and the thirdmeta-photodiode has a rod-shape comprising: a first conductivity-typesemiconductor layer, an intrinsic semiconductor layer stacked on thefirst conductivity-type semiconductor layer, and a secondconductivity-type semiconductor layer stacked on the intrinsicsemiconductor layer, and wherein the first meta-photodiode, the secondmeta-photodiode, and the third meta-photodiode respectively have a firstwidth, a second width, and a third width different from each other in adirection perpendicular to a stacking direction.
 10. The image sensor ofclaim 9, wherein the first width, the second width, and the third widthare about 50 nm to about 200 nm.
 11. The image sensor of claim 9,wherein the first wavelength band is greater than the second wavelengthband, and the second wavelength band is greater than the thirdwavelength band, and wherein the first width is greater than the secondwidth, and the second width is greater than the third width.
 12. Theimage sensor of claim 9, wherein heights of the first meta-photodiode,the second meta-photodiode, and the third meta-photodiode in thestacking direction are about 500 nm or more
 13. The image sensor ofclaim 12, wherein the heights of the first meta-photodiode, the secondmeta-photodiode, and the third meta-photodiode in the stacking directionare same as each other.
 14. The image sensor of claim 1, wherein each ofthe plurality of pixels has a width of about 250 nm to about 450 nm. 15.The image sensor of claim 1, wherein each of the plurality of pixelscomprises one of the first meta-photodiode, one of the secondmeta-photodiode, and two of the third meta-photodiode, and wherein thefirst meta-photodiode and the second meta-photodiode are provided in afirst diagonal direction, and the two third meta-photodiodes areprovided in a second diagonal direction crossing the first diagonaldirection.
 16. The image sensor of claim 1, wherein a sum of the numberof the first meta-photodiodes, the second meta-photodiodes, and thethird meta-photodiodes arranged in each of the plurality of pixels isnine, and the nine meta-photodiodes are arranged in the form of a 3×3array.
 17. The image sensor of claim 1, wherein each of the plurality ofpixels comprises one of the first meta-photodiodes, a plurality of thesecond meta-photodiodes, and a plurality of the third meta-photodiodes,and wherein the first meta-photodiode is located at the center of eachof the plurality of pixels.
 18. An image sensor comprising: a pixelarray comprising a plurality of two-dimensionally arranged pixels,wherein each of the plurality of pixels comprises: a firstmeta-photodiode configured to selectively absorb light of a firstwavelength band; a second meta-photodiode configured to selectivelyabsorb light in a second wavelength band different from the firstwavelength band; and a third meta-photodiode configured to selectivelyabsorb light of a third wavelength band different from the firstwavelength band and second wavelength band, wherein the firstmeta-photodiode, the second meta-photodiode, and the thirdmeta-photodiode are arranged in an area having a size less than adiffraction limit, and wherein a spacing between two meta-photodiodesadjacent in a first direction among the first meta-photodiode, thesecond meta-photodiode, and the third meta-photodiode is about 150 nm orless, and the spacing is at least ½ of a sum of widths of the twoadjacent meta-photodiodes.
 19. The image sensor of claim 18, wherein, inan entire area of the pixel array, the first meta-photodiode, the secondmeta-photodiode, and the third meta-photodiode arranged in each of theplurality of pixels have a same arrangement form.
 20. An electronicapparatus comprising: a lens assembly configured to form an opticalimage of an object; an image sensor configured to convert the opticalimage formed by the lens assembly into an electrical signal; and aprocessor configured to process a signal generated by the image sensor,wherein the image sensor comprises a pixel array including a pluralityof two-dimensionally arranged pixels, and each of the plurality ofpixels comprises: a first meta-photodiode configured to selectivelyabsorb light of a first wavelength band; a second meta-photodiodeconfigured to selectively absorb light of a second wavelength banddifferent from the first wavelength band; and a third meta-photodiodeconfigured to selectively absorb light of a third wavelength banddifferent from the first wavelength band and second wavelength band,wherein, the first meta-photodiode, the second meta-photodiode, and thethird meta-photodiode are arranged in an area having a size less than adiffraction limit, and wherein the first meta-photodiode, the secondmeta-photodiode, and the third meta-photodiode of one or more firstpixels in a central portion of the pixel array, among the plurality ofpixels, are arranged in a same form as the first meta-photodiode, thesecond meta-photodiode, and the third meta-photodiode of one or more ofsecond pixels in a periphery of the pixel array, among the plurality ofpixels.